Liquid crystal display device

ABSTRACT

A liquid crystal display device is provided and includes first and second substrates; first wiring provided on first substrate along first direction; second wiring provided along second direction intersecting with first direction; thin-film transistor provided at intersection between first and second wirings; drain electrode electrically connected to thin-film transistor; organic insulating film formed on thin-film transistor and covering part of drain electrode; first opening that penetrates organic insulating film and exposing drain electrode; island-shaped electrode disposed on first opening and organic insulating film, and electrically connected to drain electrode; inorganic insulating film disposed on organic insulating film, the drain electrode, and the island-shaped electrode inside the first opening; a second opening that penetrates the inorganic insulating film and exposing the drain electrode; and a pixel electrode formed on the inorganic insulating film and electrically connected to the island-shaped electrode through the second opening.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/393,316, filed on Apr. 24, 2019, which application is acontinuation of U.S. patent application Ser. No. 16/107,354, filed onAug. 21, 2018, and issued as U.S. Pat. No. 10,303,023 on May 28, 2019,which application is a continuation of U.S. patent application Ser. No.15/287,278, filed on Oct. 6, 2016, and issued as U.S. Pat. No.10,108,062 on Oct. 23, 2018, which application is a continuation of U.S.patent application Ser. No. 14/862,315, filed on Sep. 23, 2015, andissued as U.S. Pat. No. 9,482,918 on Nov. 1, 2016, which application isa continuation of U.S. patent application Ser. No. 13/944,513, filed onJul. 17, 2013, and issued as U.S. Pat. No. 9,188,821 on Nov. 17, 2015,which application claims priority to Japanese Priority PatentApplication JP 2012-166579 filed in the Japan Patent Office on Jul. 27,2012, the entire content of which is hereby incorporated by reference.

BACKGROUND

The present invention relates to a liquid crystal display apparatus, andparticularly relates to a liquid crystal display apparatus provided witha plurality of pixels.

Since a liquid crystal display apparatus has such features as lightweight, compact size and low power consumption in comparison with a CRT(Cathode Ray Tube), it is used in various types of electronic device asa display. A liquid crystal display apparatus displays an image bychanging an orientation of liquid crystal molecules aligned in apredetermined direction by an electric field and controlling the amountof light transmission through a liquid crystal layer.

A liquid crystal display apparatus has a pair of substrates including,for example, an array substrate and a color filter substrate. In thearray substrate, for example, thin film transistor (TFT) as switchingelements are formed in an array so as to correspond to each of thepixels of the liquid crystal display apparatus. In the color filtersubstrate, color filters are formed so as to correspond to each of thepixels of the liquid crystal display apparatus. A liquid crystal layeris filled in a space between the array substrate and the color filtersubstrate, and an electric field applied to the liquid crystal layer ischanged by switching the TFT in each pixel.

As a method of applying an electric field to a liquid crystal layer, themethod utilizing a vertical electric field scheme and the methodutilizing a lateral electric field scheme have been known.

In the liquid crystal display apparatus employing the lateral electricfield scheme, for example, on a liquid crystal layer side of either oneof a pair of substrates including an allay substrate and a color filtersubstrate, a pair of electrodes are provided so as to be insulated fromeach other, and an approximately lateral electric field is applied tothe liquid crystal molecules. As the liquid crystal display apparatusemploying the lateral electric field scheme, the apparatus of an IPS(In-Plane Switching) mode in which the pair of electrodes is notoverlapped with each other when seen in a plan view and the apparatus ofan FFS (Fringe Field Switching) mode in which the electrodes areoverlapped with each other have been known.

Of these, in the liquid crystal display apparatus of the FFS mode,paired electrodes including a common electrode and a pixel electrode areeach disposed on respectively different layers via an insulating film, aslit-like aperture is provided in the common electrode or the pixelelectrode on the liquid crystal layer side, and an approximately lateralelectric field passing through this slit-like aperture is applied to theliquid crystal layer. Since the liquid crystal display apparatus of theFFS mode has such effects of wide viewing angle and improved imagecontrast, it has been used more in recent years.

In each of various types of liquid crystal display devices includingsuch a liquid crystal display device of the FFS mode, surfaces of ascanning line, a signal line and a TFT formed on an array substrate arecovered with an interlayer resin film, and a pixel electrode is formedon the interlayer resin film. Moreover, a contact hole that penetratesthe interlayer resin film to reach a drain electrode of the TFT isformed on the interlayer resin film, and the pixel electrode and thedrain electrode are electrically connected with each other via thecontact hole. Furthermore, a light-shielding unit is formed on a portionbetween pixels on a liquid crystal layer side of a color filtersubstrate.

Japanese Patent Application Laid-Open Publication No. 2001-174844(Patent Document 1) and Japanese Patent Application Laid-OpenPublication No. 2001-272698 (Patent Document 2) have described atechnique in which, by forming a pixel electrode after forming a contacthole that penetrates an interlayer resin film on a drain electrode toreach the drain electrode, the pixel electrode and the drain electrodeare electrically connected with each other.

SUMMARY

In manufacturing processes of the above-mentioned liquid crystal displaydevice of the FFS mode, a lower electrode made of a transparentconductive material and an upper electrode having a slit-like apertureare formed on the surface of the interlayer resin film interposing aninter-electrode insulating film therebetween. The specific manufacturingprocess includes, for example, steps in which a hole that penetrates theinterlayer resin film on the drain electrode to reach the drainelectrode is formed, and after a lower electrode has been formed on theinterlayer resin film, an inter-electrode insulating film is formed onthe drain electrode exposed to a bottom portion of the hole as well ason the lower electrode. Next, the inter-electrode insulating film issubjected to an etching process so that a contact hole is formed, and anupper electrode is formed on the drain electrode exposed to a bottomportion of the contact hole.

In the above-mentioned manufacturing process, upon forming the lowerelectrode, the conductive film is formed on the interlayer resin film,and the aperture is formed on the lower electrode. When the aperture tobe formed on the lower electrode is formed with a protrusion from aregion in which a light-shielding unit is formed when viewed in its planview, due to a limitation in a pixel layout, a failure of displaying animage is posed since no lower electrode exists in the protruding region,and thus the aperture ratio of the pixels is actually reduced. That is,a problem arises in which an aperture ratio loss is caused. Moreover,when the area of a portion in which the scanning line (gate wiring) andthe lower electrode are overlapped with each other is not sufficientlyreduced due to the limitation in a pixel layout, another problem arisesin which a parasitic capacitance between the scanning line (gate wiring)and the lower electrode is not sufficiently reduced.

To prevent or suppress the occurrence of such an aperture ratio loss orto sufficiently reduce the parasitic capacitance between the scanningline (gate wiring) and the lower electrode, a method may be proposed inwhich the aperture to be formed on the lower electrode is formed at aposition deviated from a position of the drain electrode.

However, in the above-mentioned manufacturing process, upon etching theinter-electrode insulating film to form the contact hole, thecross-sectional shape of the contact hole is prone to be a so-calledreverse-tapered shape. When the contact hole has the reverse-taperedshape in its cross-sectional shape, both of an upper electrode formed ona side surface portion of the contact hole and an upper electrode formedon a bottom portion of the contact hole fail to be connected to eachother as an integral unit, thereby making it difficult to reliablyconnect the upper electrode and the drain electrode to each otherelectrically. Even when the aperture to be formed on the lower electrodeis formed at a position deviated from the position of the drainelectrode, the cross-sectional shape of the contact hole is prone to bethe reverse-tapered shape, thereby making it difficult to reliablyconnect the upper electrode and the drain electrode to each otherelectrically.

The present invention has been made to solve the above-mentionedconventional problems, and its preferred aim is to provide a liquidcrystal display device in which an upper electrode and a drain electrodeare reliably connected to each other electrically with preventing orsuppressing occurrence of an aperture ratio loss, or with sufficientlyreducing parasitic capacitance between a scanning line and a lowerelectrode.

The typical ones of the inventions disclosed in the present applicationwill be briefly described as follows.

A liquid crystal display device in accordance with a typical embodimentincludes an interlayer resin film formed on a drain electrode that isformed on an array electrode, and a hole is formed in the interlayerresin film, with an island-shaped electrode being formed on the drainelectrode exposed to the hole separately from a lower electrode.Moreover, on the island-shaped electrode, an inter-electrode insulatingfilm is formed, and a contact hole is formed in the inter-electrodeinsulating film, with an upper electrode being formed on theisland-shaped electrode exposed to a bottom portion of the contact hole.

Moreover, a method of manufacturing a liquid crystal display device inaccordance with a typical embodiment includes steps of forming aninterlayer resin film on a drain electrode formed on an array substrate,forming a hole in the interlayer resin film, and forming a conductivefilm on the drain electrode exposed to the hole. By carrying out apatterning process on the conductive film, an island-shaped electrode isformed separately from the lower electrode. Next, an inter-electrodeinsulating film is formed on the island-shaped electrode, a contact holeis formed in the inter-electrode insulating film, and an upper electrodeis formed on the island-shaped electrode exposed to a bottom portion ofthe contact hole.

The effects obtained by typical aspects of the present invention will bebriefly described below.

According to the typical embodiments, the upper electrode and the drainelectrode can be reliably connected with each other electrically withpreventing or suppressing an occurrence of an aperture ratio loss, orwith sufficiently reducing parasitic capacitance between the scanningline and the lower electrode.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view showing an outline of a liquid crystal displayapparatus of the first embodiment;

FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1;

FIG. 3 is a cross-sectional view taken along the line B-B in FIG. 1;

FIG. 4 is a plan view showing a part of one subpixel near a drainelectrode in the liquid crystal display apparatus of the firstembodiment in an enlarged manner;

FIG. 5 is a cross-sectional view taken along the line C-C in FIG. 4;

FIG. 6 is a cross-sectional view taken along the line D-D in FIG. 4;

FIG. 7 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 8 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 9 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 10 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 11 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 12 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 13 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 14 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 15 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 16 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 17 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 18 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 19 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 20 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thefirst embodiment;

FIG. 21 is a plan view showing a part of one subpixel near a drainelectrode in the liquid crystal display apparatus of a comparativeexample in an enlarged manner;

FIG. 22 is a cross-sectional view taken along the line C-C in FIG. 21;

FIG. 23 is a cross-sectional view taken along the line D-D in FIG. 21;

FIG. 24 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thecomparative embodiment;

FIG. 25 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thecomparative embodiment;

FIG. 26 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thecomparative embodiment;

FIG. 27 is a plan view showing a part of one subpixel near a drainelectrode in the liquid crystal display apparatus of a second embodimentin an enlarged manner;

FIG. 28 is a cross-sectional view taken along the line C-C in FIG. 27;

FIG. 29 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thesecond embodiment;

FIG. 30 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thesecond embodiment;

FIG. 31 is a cross-sectional view showing the principal part in themanufacturing process of the liquid crystal display apparatus of thesecond embodiment; and

FIG. 32 is a perspective view showing a mobile phone as an example of anelectronic device of a third embodiment.

DETAILED DESCRIPTION

Also, in the embodiments described below, when referring to the numberof elements (including number of pieces, values, amount, range, and thelike), the number of the elements is not limited to a specific numberunless otherwise stated or except the case where the number isapparently limited to a specific number in principle. The number largeror smaller than the specified number is also applicable.

Further, in the embodiments described below, it goes without saying thatthe components (including element steps) are not always indispensableunless otherwise stated or except the case where the components areapparently indispensable in principle. Similarly, in the embodimentsdescribed below, when the shape of the components, positional relationthereof, and the like are mentioned, the substantially approximate andsimilar shapes and the like are included therein unless otherwise statedor except the case where it is conceivable that they are apparentlyexcluded in principle. The same goes for the numerical value and therange described above.

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. Note that componentshaving the same function are denoted by the same reference symbolsthroughout the drawings for describing the embodiments, and therepetitive description thereof will be omitted. Also, in the followingembodiments, the descriptions of the same or similar components are notrepeated in principle except when particularly necessary.

Furthermore, in some drawings used in the following embodiments,hatching is omitted even in a cross-sectional view so as to make thedrawings easy to see. Also, hatching is used even in a plan view so asto make the drawings easy to see.

FIRST EMBODIMENT

<Liquid crystal display apparatus>

A liquid crystal display apparatus 10 of the first embodiment of thepresent invention will be described with reference to drawings.

First, a general configuration of the liquid crystal display apparatus10 of the first embodiment will be described with reference to FIG. 1 toFIG. 3.

FIG. 1 is a plan view showing an outline of the liquid crystal displayapparatus of the first embodiment. FIG. 2 is a cross-sectional viewtaken along the line A-A in FIG. 1. FIG. 3 is a cross-sectional viewtaken along the line B-B in FIG. 1.

For example, the liquid crystal display apparatus 10 of the firstembodiment is a liquid crystal display apparatus of an FFS modeutilizing a lateral electric field scheme for color display, and isprovided with a plurality of pixels 11 as shown in FIG. 1. Also, in theconfiguration of the liquid crystal display apparatus 10 of the firstembodiment, as shown in FIG. 2 and FIG. 3, a liquid crystal layer LC issandwiched between an allay substrate AR and a color filter substrateCF. More specifically, the liquid crystal display apparatus 10 includesthe array substrate AR, the color filter substrate CF arranged so as tobe opposed to the array substrate AR, and the liquid crystal layer LCsandwiched between the array substrate AR and the color filter substrateCF. The pixels 11 operate in the FFS mode and can use the liquid crystallayer LC in common. The plurality of pixels 11 are arranged in a rowdirection (X axis direction of FIG. 1) and a column direction (Y axisdirection of FIG. 1). The pixel 11 is made up of, for example, subpixels12 for representing three colors of red (R), green (G) and blue (B), andthe color of each pixel 11 is determined by the mixture of the lights ofthese colors.

FIG. 1 shows an example of three-color display, but the liquid crystaldisplay apparatus 10 is not limited to the three-color display. Forexample, the pixel 11 may be made up of the subpixels 12 of two or lesscolors. Alternatively, the pixel 11 may be made up of the subpixels 12of four or more colors (the same is true in the following embodiments).

In the specification of the present application, a region R1 is definedas a region corresponding to one subpixel 12, but one subpixel may bedefined in a different manner as long as the definition is made so thatperiodical structure is repeated for each subpixel.

Also, FIG. 1 shows the state in which the part of the color filtersubstrate CF other than the photo spacer (spacer portion) 34 (see FIG.2) is removed (transparent) for the sake of easy understanding (the sameis true in FIG. 4 to FIG. 6, FIG. 13 and FIG. 15 to FIG. 18 below).Furthermore, FIG. 1 shows the state in which a gate insulating film 21(see FIG. 2), a semiconductor layer 22 (see FIG. 2), an interlayer resinfilm (planarization film) 23 (see FIG. 2), a lower electrode 24 (seeFIG. 2) and an inter-electrode insulating film 25 (see FIG. 2) of thearray substrate AR are removed (transparent) for the sake of easyunderstanding (the same is true in FIG. 4 to FIG. 6, FIG. 13 and FIG. 15to FIG. 18 below). Moreover, in FIG. 1, an outer periphery of a lightshielding portion 31 (see FIG. 2) provided in the color filter substrateCF is illustrated by a two-point chain line for the sake of easyunderstanding (the same is true in FIG. 4 to FIG. 6 and FIG. 16 to FIG.18 below). In addition, in FIG. 1, with respect to the photo spacer(spacer portion) 34, only the outer periphery thereof is illustrated bya solid line for the sake of easy understanding (the same is true inFIG. 4, FIG. 5 and FIG. 16 to FIG. 18 below).

As shown in FIG. 1, the subpixel 12 has a scanning line (gate wiring) 14and a signal line (source wiring) 14 on the array substrate AR. Thescanning line (gate wiring) 13 extends in the X axis direction and ismade of, for example, opaque metal such as aluminum (Al) or molybdenum(Mo). The signal line (source wiring) 14 extends in the Y axis directionand is made of, for example, opaque metal such as aluminum (Al) ormolybdenum (Mo). Also, the subpixel 12 has a TFT (Thin-Film Transistor)16 provided on the array substrate AR and at an intersecting portion 15of the scanning line (gate wiring) 13 and the signal line (sourcewiring) 14.

In the specification of the present application, the intersectingportion 15 is defined as including a portion at which the scanning line(gate wiring) 13 and the signal line (source wiring) 14 intersect and aportion around it, and it includes also the region in which the TFT(Thin-Film Transistor) 16 having a drain electrode DE is formed.

Also, the Y axis direction is a direction intersecting with the X axisdirection, and the Y axis direction is preferably a direction orthogonalto the X axis direction.

As shown in FIG. 2 and FIG. 3, the array substrate AR has a firsttransparent substrate 20 as a base substrate. The first transparentsubstrate 20 is made of a transparent insulating material such as glass,quartz, or plastic. Note that, in FIG. 2 and FIG. 3, hatchings of thefirst transparent substrate 20, the gate insulating film 21, theinterlayer resin film (planarization film) 23 and the inter-electrodeinsulating film 25 are omitted so as to make the drawings easy to see(the same is true in FIG. 7 and FIG. 8 to FIG. 10 below).

On the first transparent substrate 20, the scanning line (gate wiring)13 is formed on a side facing the liquid crystal layer LC. As describedabove, the scanning line (gate wiring) 13 extends in the row direction(X axis direction) and is made of, for example, opaque metal such asaluminum (Al) or molybdenum (Mo). A gate electrode GE extends from thescanning line (gate wiring) 13.

A transparent gate insulating film 21 made of, for example, siliconnitride or silicon oxide is stacked (formed) so as to cover the scanningline (gate wiring) 13 and the gate electrode GE. Also, on the gateinsulating film 21 overlapped with the gate electrode GE when seen in aplan view, a semiconductor layer 22 made of, for example, amorphoussilicon or polycrystalline silicon is formed.

On the gate insulating film 21, the signal line (source wiring) 14 isformed. As described above, the signal line (source wiring) 14 extendsin the column direction (Y axis direction) and is made of, for example,opaque material such as aluminum (Al) or molybdenum (Mo). A sourceelectrode SE extends from the signal line (source wiring) 14. The sourceelectrode SE is partially in contact with a surface of the semiconductorlayer 22.

On the gate insulating film 21, the drain electrode DE made of the samematerial as the signal line (source wiring) 14 and formed simultaneouslytherewith is provided. The drain electrode DE is disposed near thesource electrode SE and is partially in contact with the semiconductorlayer 22.

When seen in a plan view, the region surrounded by the adjacent twoscanning lines (gate wiring) 13 and the adjacent two signal lines(source wiring) 14 delimits the subpixel 12. More specifically, thesubpixel 12 is demarcated by the adjacent two scanning lines (gatewiring) 13 and the adjacent two signal lines (source wiring) 14. Then,in the subpixel 12, the gate electrode GE, the gate insulating film 21,the semiconductor layer 22, the source electrode SE and the drainelectrode DE constitute the TFT 16 serving as a switching element.

Further, the interlayer resin film (planarization film) 23 made of, forexample, a transparent resin material such as photoresist is stacked(formed) so as to cover exposed portions of the signal line (sourcewiring) 14, the TFT 16 and the gate insulating film 21. Morespecifically, the interlayer resin film (planarization film) 23 isformed on the TFT 16 including the drain electrode DE. The interlayerresin film (planarization film) 23 covers the exposed portions of thesignal line (source wiring) 14, the TFT 16 and the gate insulating film21, and planarizes uneven surfaces of the signal line (source wiring)14, the TFT 16 and the gate insulating film 21.

Note that, as an underlayer of the interlayer resin film (planarizationfilm) 23, for example, a transparent passivation film made of siliconnitride or silicon oxide can be stacked (formed) so as to cover all orpart of the exposed portions of the signal line (source wiring) 14, theTFT 16 and the gate insulating film 21. Furthermore, the interlayerresin film (planarization film) 23 can be stacked (formed) so as tocover the passivation film.

The lower electrode 24 made of a transparent conductive material such asITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is formed so as tocover the interlayer resin film (planarization film) 23. The lowerelectrode 24 is integrally and continuously formed in an approximatelyentire transparent region including the region of each subpixel 12, andoperates as a common electrode.

The transparent inter-electrode insulating film 25 made of, for example,silicon nitride or silicon oxide is stacked (formed) so as to cover thelower electrode 24. Also, the upper electrode 26 made of, for example, atransparent conductive material such as ITO or IZO is formed so as tocover the inter-electrode insulating film 25. The upper electrode 26 isformed at a position overlapped with the lower electrode 24 in eachsubpixel 12 when seen in a plan view. More specifically, in the subpixel12, the lower electrode 24 and the upper electrode 26 are opposed toeach other with interposing (via) the inter-electrode insulating film 25therebetween.

In the subpixel 12, a contact hole 27 which penetrates through theinter-electrode insulating film 25 and the interlayer resin film(planarization film) 23 to reach the drain electrode DE of the TFT 16 isformed at a position overlapped with the drain electrode DE when seen ina plan view. At a bottom portion of the contact hole 27, the drainelectrode DE is exposed. The upper electrode 26 is electricallyconnected to the drain electrode DE exposed at the bottom portion of thecontact hole 27. Therefore, the upper electrode 26 operates as a pixelelectrode.

Note that, in FIG. 1, for the sake of easy understanding, only a part ofthe upper electrode 26 is shown (the same is true in FIG. 4, FIG. 5, andFIG. 16 to FIG. 18 below). Also, in the illustration in FIG. 1, an edgeportion of the upper electrode 26 is not overlapped with the lightshielding portion 31 described later for the sake of easy understanding,but it is also possible to form the upper electrode 26 so that the edgeportion of the upper electrode 26 is overlapped with the light shieldingportion 31 (the same is true in FIG. 4, FIG. 5, and FIG. 16 to FIG. 18below).

Also, an alignment film (not shown) made of, for example, polyimide isstacked (formed) so as to cover the upper electrode 26. In thisalignment film, the rubbing process is performed in a positive directionin the Y axis direction of FIG. 1.

Slit-like apertures 28 extending in an extending direction of the signalline (source wiring) 14 are formed in the upper electrode 26 formed inthe subpixel 12. When the X axis direction is defined as a lateraldirection and the Y axis direction is defined as a longitudinaldirection, the subpixel 12 has an elongated shape whose length in thelateral direction is shorter than the length in the longitudinaldirection. Therefore, when the slit-like apertures 28 are formed toextend in the lateral direction, the number of both ends of theslit-like apertures 28 is increased. The end portions of the slit-likeapertures 28 become abnormal alignment regions of liquid crystalmolecules and cause the decrease of the aperture ratio. Therefore, inthe liquid crystal display apparatus 10 of the first embodiment, asshown in FIG. 1, the extending direction of the slit-like apertures 28is made closer to the Y axis direction rather than the X axis direction,thereby reducing the number of end portions of the slit-like apertures28 to suppress the decrease of the aperture ratio.

The color filter substrate CF uses a second transparent substrate 30 asa base substrate thereof. The second transparent substrate 30 is made ofa transparent insulating material such as glass, quartz, or plastic. Inthe subpixel 12, a light shielding portion (black matrix) 31 having alight shielding property and made of, for example, resin or metal isformed at a position opposed to the scanning line (gate wiring) 13 andthe signal line (source wiring) 14. Also, in the subpixels 12, colorfilter layers 32 through which lights of different colors (for example,red (R), green (G) and blue (B)) pass are formed for each of thesubpixels 12. Therefore, the light shielding portion (black matrix) 31is provided between the subpixels 12 each having the color filter layer32 formed therein. Note that, in FIG. 2 and FIG. 3, hatchings of thesecond transparent substrate 30, the color filter layer 32 and anovercoat layer 33 are omitted so as to make the drawings easy to see(the same is true in FIG. 7, FIG. 11 and FIG. 12 below).

Note that the ratio of the area occupied by the part not covered by thelight shielding portion 31 in the area of the subpixel 12 (area of theregion R1) corresponds to the aperture ratio.

The overcoat layer 33 made of, for example, a transparent resin materialsuch as photoresist is stacked (formed) so as to cover the lightshielding portion 31 and the color filter layer 32 of each subpixel 12.The overcoat layer 33 of each subpixel 12 is formed so as to planarizethe unevennesses due to the color filter layers 32 of different colorsand prevent foreign materials from the light shielding portion 31 andthe color filter layer 32 from entering the liquid crystal layer LC.

On the overcoat layer 33, the photo spacer (spacer portion) 34 formaintaining a space between the array substrate AR and the color filtersubstrate CF and keeping the liquid crystal layer LC at a predeterminedthickness is formed. The photo spacer (spacer portion) 34 is made of,for example, a transparent resin material such as photoresist. Then, analignment film (not shown) made of, for example, polyimide is formed soas to cover the overcoat layer 33 and the photo spacer (spacer portion)34. In this alignment film (not shown) formed in the color filtersubstrate CF, the rubbing process in the direction reverse to that ofthe alignment film (not shown) formed in the array substrate AR isperformed.

The array substrate AR and the color filter substrate CF described aboveare disposed so as to be opposed to each other (opposed disposition) viathe photo spacer (spacer portion) 34 for maintaining a space between thearray substrate AR and the color filter substrate CF. Also, though notshown, a sealing member is provided between an outer periphery of thearray substrate AR and an outer periphery of the color filter substrateCF. Then, between the array substrate AR and the color filter substrateCF disposed so as to be opposed to each other (opposed disposition), forexample, the liquid crystal layer LC of homogeneous alignment is filled.Note that, in FIG. 2 and FIG. 3, hatching of the liquid crystal layer LCis omitted so as to make the drawings easy to see (the same is true inFIG. 7 below).

In the example shown in FIG. 1, the photo spacer (spacer portion) 34 isprovided so as to correspond to all of the subpixels 12, but it is notalways necessary to provide the photo spacer (spacer portion) 34 so asto correspond to all of the subpixels 12. For example, one photo spacer(spacer portion) 34 may be provided for each two subpixels 12 arrangedalong the extending direction (X axis direction) of the scanning line(gate wiring) 13. Also, one photo spacer (spacer portion) 34 may beprovided for each three subpixels 12 arranged along the extendingdirection (X axis direction) of the scanning line (gate wiring) 13.Alternatively, one photo spacer (spacer portion) 34 may be provided foreach two or more subpixels 12 arranged along the extending direction (Yaxis direction) of the signal line (source wiring) 14.

In accordance with the above-described arrangement, in the subpixel 12,when the TFT 16 is brought into an ON-state, an electric field isgenerated between the lower electrode 24 and the upper electrode 26 sothat the orientation of liquid crystal molecules in the liquid crystallayer LC is changed. Thus, the light transmittance of the liquid crystallayer LC is changed so that an image is displayed in the FFS mode.Moreover, areas in which the lower electrode 24 and the upper electrode26 are opposed to each other, with (via) the inter-electrode insulatingfilm 25 interposed therebetween, are allowed to form an auxiliarycapacitance so that even when the TFT 16 is brought into an OFF-state,the electric field between the lower electrode 24 and the upperelectrode 26 is maintained for a predetermined period of time.

In the present first embodiment, the slit-like aperture 28 is providedwith a bend portion 28 a in its middle portion, for example, in thecenter portion along the extending direction (Y axis direction) of theslit-like aperture 28. On a portion closer to the positive direction (+Ydirection) side in the Y axis direction from the bend portion 28 a, theextending direction of the slit-like aperture 28 is tilted by +α(supposing that the clockwise direction is positive and that α ispositive) relative to a rubbing direction (positive direction in the Yaxis direction). Moreover, on a portion closer to the negative direction(−Y direction) side in the Y axis direction from the bend portion 28 a,the extending direction of the slit-like aperture 28 is tilted by −αrelative to the rubbing direction (positive direction in the Y axisdirection). The tilt angle α may be set to, for example, 5 degrees.

When all the slit-like apertures 28 are tilted in the clockwisedirection or in the counter-clockwise direction relative to the rubbingdirection (positive direction in the Y axis direction), since liquidcrystal molecules are twisted in one direction, a color-varyingphenomenon occurs depending on viewing directions. This phenomenon iscaused because an apparent hue difference (retardation) is varieddepending on directions in which the liquid crystal molecules areviewed. Therefore, in the liquid crystal display device 10 of thepresent first embodiment, in order to reduce the hue difference(retardation) generated depending on directions in which the liquidcrystal molecules are viewed, the slit-like aperture 28 is provided withthe bend portion 28 a in its middle portion, for example, in the centerportion along the extending direction of the slit-like aperture 28. Inthe example shown in FIG. 1, the slit-like aperture 28 is bent by anangle of 2α before and after the bend portion 28 a along the Y axisdirection.

In the present first embodiment, the extending direction of the signalline (source wiring) 14 is not tilted relative to the rubbing direction(positive direction in the Y axis direction), but made in parallel withthe Y axis direction. That is, in the present first embodiment, thesignal line (source wiring) 14 is not bent, but linearly formed. Even inthis structure, for example, when the tilt angle α of the slit-likeaperture 28 relative to the rubbing direction (positive direction in theY axis direction) is small, the direction and size of the electric fieldgenerated between the upper electrode 26 and the lower electrode 24 canbe made virtually uniform within a single subpixel.

Alternatively, within the single subpixel 12, at a portion closer to thepositive direction (+Y direction) side in the Y axis direction from thecenter portion, the extending direction of the signal line (sourcewiring) 14 can be tilted by +α relative to the rubbing direction(positive direction in the Y axis direction). Moreover, at a portioncloser to the negative direction (−Y direction) side in the Y axisdirection from the center portion, the extending direction of the signalline (source wiring) 14 can be tilted by −α relative to the rubbingdirection (positive direction in the Y axis direction). That is, inaccordance with the slit-like aperture 28, a bend portion can also beformed in the center portion of the signal line (source wiring) 14 alongthe Y axis direction.

Referring to FIGS. 4 to 6, the following description will explain thelower electrode 24, the inter-electrode insulating film 25, the upperelectrode 26 and the contact hole (opening) 27 of the liquid crystaldisplay device 10 of the present first embodiment in detail.

FIG. 4 is a plan view that shows a portion near the drain electrode ofone of the subpixels in the liquid crystal display device of the firstembodiment in an enlarged manner. FIG. 5 is a cross-sectional view takenalong the line C-C of FIG. 4. FIG. 6 is a cross-sectional view takenalong the line D-D of FIG. 4.

Additionally, to facilitate understanding, FIG. 4 illustrates a(perspective) state from which the color filter substrate CF is removed.Moreover, to facilitate understanding, FIG. 4 also illustrates a statein which, from the array substrate AR, the gate insulating film 21 (seeFIG. 5), the semiconductor layer 22 (see FIG. 5), the interlayer resinfilm (planarization film) 23 (see FIG. 5), the inter-electrodeinsulating film 25 (see FIG. 5) and the upper electrode 26 (see FIG. 5)are removed (as a perspective view) so that the lower electrode 24 isseen on the uppermost surface. Moreover, to facilitate understanding,FIG. 4 also illustrates a peripheral portion of a bottom portion 27 a ofthe contact hole (opening) 27 formed on the inter-electrode insulatingfilm 25 (see FIG. 5).

On the interlayer resin film (planarization film) 23, when seen in itsplan view, a hole (opening) 41 that penetrates the interlayer resin film(planarization film 23) to reach a drain electrode DE is formed at aposition that overlaps with the drain electrode DE. Onto a bottomportion 41 a of the hole (opening) 41, the drain electrode DE isexposed. On the drain electrode DE exposed to the bottom portion 41 a ofthe hole (opening) 41, an island-shaped electrode 42 is formed.Moreover, when seen in its plan view, on a region apart from the bottomportion 41 a of the hole (opening) 41, the lower electrode 24 is formedon the interlayer resin film (planarization film) 23. Additionally, theisland-shaped electrode 42 is formed not only on the drain electrode DEexposed to the bottom portion 41 a of the hole (opening) 41, but also ona side surface portion 41 b of the hole (opening) 41.

As described above, the lower electrode 24 is continuously formedintegrally on virtually the entire transparent region including theregion of each of the subpixels 12. However, as shown in FIG. 4, on thelower electrode 24, an opening 43 is formed so that, when seen in itsplan view, the island-shaped electrode 42 and the lower surface portion41 a of the hole (opening) 41 are disposed inside the opening 43. Thelower surface of the island-shaped electrode 42 is made in contact withthe upper surface of the drain electrode DE, with the upper surface ofthe island-shaped electrode 42 being made in contact with the lowersurface of an upper electrode 26, which will be described later;however, the island-shaped electrode 42 is made in contact neither withany of the electrodes, nor with any of the wiring, except for the drainelectrode DE and the upper electrode 26. In other words, although theisland-shaped electrode 42 is surrounded by the lower electrode 24, whenseen in its plan view, it is separated from the lower electrode 24 sothat it has the island shape when seen in its plan view.

On the island-shaped electrode 42, on the lower electrode 24, as well ason the interlayer resin film (planarization film) 23 exposed to a region44 between the island-shaped electrode 42 and the lower electrode 24,when seen in its plan view, the inter-electrode insulating film 25 isformed. On the inter-electrode insulating film 25, when seen in its planview, a contact hole (opening) 27 that penetrates the inter-electrodeinsulating film 25 to reach the island-shaped electrode 42 is formed ata position that overlaps with the island-shaped electrode 42. On thebottom portion 27 a of the contact hole (opening) 27, the island-shapedelectrode 42 is exposed. On the island-shaped electrode 42 exposed tothe bottom portion 27 a of the contact hole (opening) 27 as well as onthe inter-electrode insulating film 25 on the periphery of theisland-shaped electrode 42, when seen in its plan view, the upperelectrode 26 is formed.

As described above, the lower surface of the island-shaped electrode 42is made in contact with the upper surface of the drain electrode DE, andthe upper surface of the island-shaped electrode 42 is made in contactwith the lower surface of the upper electrode 26. Therefore, the upperelectrode 26 and the drain electrode DE are electrically connected witheach other through the island-shaped electrode 42.

As shown in FIGS. 5 and 6, on an edge portion 45 of the bottom portion27 a of the contact hole (opening) 27, the island-shaped electrode 42 issandwiched between the inter-electrode insulating film 25 and theinterlayer resin film (planarization film) 23 so that theinter-electrode insulating film 25 and the interlayer resin film(planarization film) 23 are not directly made in contact with eachother. By using such a structure, upon forming the contact hole(opening) 27, it is possible to prevent or suppress the interlayer resinfilm (planarization film) 23 from being scraped off (hollowed) togetherwith the inter-electrode insulating film 25. As a result, it is possibleto prevent or suppress the width dimension of the contact hole (opening)27 from becoming larger toward the lower side to cause a reverse-taperedshape in the cross-sectional shape of the contact hole (opening) 27.Thus, upon forming the upper electrode 26 on the contact hole (opening)27, it is possible to prevent or suppress an occurrence of a so-called“step disconnection or step fault” in which the upper electrode 26,formed on the side surface portion 27 b of the contact hole (opening)27, and the upper electrode 26, formed on the bottom portion 27 a of thecontact hole (opening) 27, are not connected with each other.

Moreover, as will be described later with reference to FIGS. 11 to 14,the island-shaped electrode 42 is formed through processes in which aconductive film 46 (see FIG. 11 to be described later) to be formed intothe lower electrode 24 is formed on the entire surface of the arraysubstrate AR and the same conductive film 46 thus formed is subjected toa patterning process. With this structure, the island-shaped electrode42 can be formed simultaneously with the lower electrode 24 in theprocess for forming the lower electrode 24, without the need for addingany new process. Moreover, since the island-shaped electrode 42 and thelower electrode 24 are formed by the same conductive film 46, theisland-shaped electrode 42 and the lower electrode 24 are desirablyformed by using the same material.

In the liquid crystal display device 10 of the present first embodiment,preferably, the contact hole (openings) 27 is formed at a positiondeviating from the hole (opening) 41 in a direction intersecting withthe scanning line (gate wiring) 13, for example, along the extendingdirection (Y axis direction of FIG. 4) of the signal line (sourcewiring) 14. With this structure, it is possible to increase the amountof allowance by which, when seen in its plan view, the position at whichthe opening 43 is formed on the lower electrode 24 is allowed to deviatealong the Y axis direction from a position at which a light-shieldingunit 31 is formed. For this reason, it becomes possible to prevent orsuppress a reduction of an aperture ratio (aperture ratio loss) in thesubpixels 12.

More preferably, when seen in its plan view, the opening 43 of the lowerelectrode 24 is formed in such a manner as to traverse the scanning line(gate wiring) 13. By forming the opening 43 so as to traverse thescanning line (gate wiring) 13, it is possible to reduce an area inwhich the lower electrode 24 and the scanning line (gate wiring) 13 areoverlapped with each other. For this reason, a parasitic capacitancebetween the lower electrode 24 and the scanning line (gate wiring) 13can be reduced.

Additionally, in the present specification, the point that the contacthole (opening) 27 is formed at a position deviating from the hole(opening) 41 along the Y axis direction means that, when seen in itsplan view, the position of the center of gravity of the bottom portion27 a of the contact hole (opening) 27 and the position of the center ofgravity of the bottom face 41 a of the hole (opening) 41 are located atdifferent positions along the Y axis direction. That is, the position ofthe center of gravity of the bottom portion 27 a of the contact hole(opening) 27 and the position of the center of gravity of the bottomface 41 a of the hole (opening) 41 are separated from each other alongthe Y axis direction.

<Manufacturing Process of Liquid Crystal Display Device>

Next, referring to FIGS. 7 to 20, the following description will explainmanufacturing processes of a liquid crystal display device 10 of thepresent first embodiment. FIGS. 7 to 20 are cross-sectional viewsshowing the principal part during manufacturing processes of the liquidcrystal display device in accordance with first embodiment. FIGS. 7, 9,11, 13, 15 and 17 indicate cross sections corresponding to the crosssections shown in the aforementioned FIG. 5. Moreover, FIGS. 8, 10, 12,14, 16 and 18 indicate cross sections corresponding to the crosssections shown in the aforementioned FIG. 6.

First, as shown in FIGS. 7 and 8, on a surface (first main surface) of afirst transparent substrate 20, by using a photolithography techniqueand etching, a gate electrode GE composed of an Al (aluminum) layer andan Mo (molybdenum) layer and a scanning line (gate wiring) 13 areformed, for example, in the order from the lower layer to the upperlayer.

Next, as shown in FIGS. 7 and 8, on the gate electrode GE as well as onthe first transparent substrate 20, a gate insulating film 21 made of,for example, silicon nitride or the like, is formed by using a CVD(Chemical Vapor Deposition) method. Moreover, by using thephotolithography technique and etching, a semiconductor layer 22 havinga two-layer structure of, for example, an a-Si (amorphous silicon) layerand an n⁺ -Si (n⁺ -type silicon) layer having an n-type conductivity isformed so as to be overlapped with the gate electrode GE via the gateinsulating film 21, when seen in its plan view.

Next, as shown in FIGS. 7 and 8, on the semiconductor layer 22, a sourceelectrode SE, composed of an Mo layer, an Al layer and an Mo layer inthe order from the lower layer to the upper layer, a signal line (sourcewiring) 14 and a drain electrode DE are formed so as to be overlappedwith the gate electrode GE and the semiconductor layer 22 and also to beelectrically connected with the semiconductor layer 22, when seen in itsplan view. Thus, a TFT (thin-film transistor) 16 is formed.

Next, as shown in FIGS. 7 and 8, on the signal line (source wiring) 14,the source electrode SE, the semiconductor layer 22 and the drainelectrode DE, as well as on the gate insulating film 21, the interlayerresin film (planarization film) 23 is formed. That is, the interlayerresin film (planarization film) 23 is formed in a manner so as to coverthe exposed portions of the signal line (source wiring) 14, the sourceelectrode SE and the semiconductor layer 22, as well as the exposedportions of the drain electrode DE and the gate insulating film 21. Theinterlayer resin film (planarization film) 23 is formed as a protectivefilm made of an acryl-based photosensitive resin, by using, for example,an application method.

Additionally, a transparent passivation film made of, for example,silicon nitride, silicon oxide, or the like may be stacked (formed) in amanner so as to cover one portion or the entire portion of the exposedportions of the signal line (source wiring) 14, the source electrode SEand the semiconductor layer 22, as well as the exposed portions of thedrain electrode DE and the gate insulating film 21. Then, the interlayerresin film (planarization film) 23 may be stacked (formed) so as tocover the passivation film.

Next, a portion of the interlayer resin film (planarization film) 23,which is formed on the drain electrode DE, is removed by using aphotolithography technique and etching. Thus, as shown in FIGS. 4, 9 and10, a hole (opening) 41, which penetrates the interlayer resin film(planarization film) 23 to reach the drain electrode DE, is formed at aposition that is overlapped with the drain electrode DE, when seen inits plan view. In this case, the drain electrode DE is exposed to thebottom portion 41 a of the hole (opening) 41.

As shown in FIGS. 11 and 12, on the drain electrode DE exposed to thebottom portion 41 a of the hole (opening) 41 as well as on theinterlayer resin film (planarization film) 23, a conductive film 46 madeof ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide) or the like is formedby using, for example, a sputtering method. In other words, theconductive film 46 is formed in a manner so as to cover the drainelectrode DE exposed to the bottom portion 41 a of the hole (opening) 41and the interlayer resin film (planarization film) 23.

Next, a portion (see FIG. 4) inside a frame-shaped region 44 is removedby using a photolithography technique and etching so that, when seen inits plan view, an island-shaped electrode 42 is allowed to remain at aregion overlapped with at least one portion of the drain electrode DEand the hole (opening) 41 within the conductive film 46 thus formed.That is, the portion inside the frame-shaped region 44 (see FIG. 4) ofthe conductive film 46 is bored. In this manner, by carrying out apatterning process on the conductive film 46, the lower electrode 24made of the conductive film 46 is formed as shown in FIGS. 4, 13 and 14.Moreover, the opening 43 is formed on the lower electrode 24simultaneously as the formation of the lower electrode 24, and theisland-shaped electrode 42 made of the conductive film 46 is formedwithin the opening 43. At this time, the bottom portion 41 a of the hole(opening) 41 is disposed inside the opening 43 when seen in its planview. Thus, it becomes possible to prevent the lower electrode 24 (seeFIG. 5) and the upper electrode 26 (see FIG. 5) from causing shortcircuits electrically.

As shown in FIGS. 13 and 14, in the present first embodiment, theisland-shaped electrode 42 is formed on the bottom portion 41 a of thehole (opening) 41 as well as on a side surface portion 41 b of the hole(opening) 41.

Next, as shown in FIGS. 15 and 16, on the island-shaped electrode 42, onthe lower electrode 24 as well as on the interlayer resin film(planarization film) 23 that is exposed to a region (frame-shapedregion) 44 between the island-shaped electrode 42 and the lowerelectrode 24, when seen in its plan view, an inter-electrode insulatinglayer 25 made of silicon nitride or the like is formed by using, forexample, the CVD method. That is, the inter-electrode insulating layer25 is formed in a manner so as to cover the island-shaped electrode 42,the lower electrode 24 and the interlayer resin film (planarizationfilm) 23 that is exposed to the region (frame-shaped region) 44 (seeFIG. 4) between the island-shaped electrode 42 and the lower electrode24, when seen in its plan view.

Next, a portion of the inter-electrode insulating film 25 on which thecontact hole (opening) 27 has been formed is removed by using aphotolithography technique and etching. Thus, as shown in FIGS. 4, 17and 18, a contact hole (opening) 27, which penetrates theinter-electrode insulating film 25 to reach the island-shaped electrode42, when seen in its plan view, is formed. Moreover, the island-shapedelectrode 42 is exposed to the bottom portion 27 a of the contact hole(opening) 27.

As shown in FIG. 18, in the present first embodiment, the contact hole(opening) 27 is formed at a position deviating from the hole (opening)41 along a direction (the Y axis direction of FIG. 4) intersecting withthe extending direction of the scanning line (gate wiring) 13. With thisarrangement, it is possible to increase the amount of allowance bywhich, when seen in its plan view, the position at which the opening 43is formed on the lower electrode 24 is allowed to deviate along the Yaxis direction from a position at which the light-shielding unit 31 isformed.

Next, the upper electrode 26 made of ITO, IZO or the like is formed onthe island-shaped electrode 42 as well as on the inter-electrodeinsulating film 25 by using, for example, a sputtering method. That is,the upper electrode 26 is formed in a manner so as to cover theisland-shaped electrode 42 and the inter-electrode insulating film 25.Thus, as shown in FIGS. 5 and 6, the upper electrode 26 and the drainelectrode DE are electrically connected with each other via the contacthole (opening) 27. Moreover, the upper electrode 26 and the drainelectrode DE are electrically connected with each other via theisland-shaped electrode 42.

Then, though not shown in FIGS. 5 and 6, the slit-like aperture 28 (seeFIG. 1) is formed on the formed upper electrode 26 by thephotolithography and etching. Thereafter, though not shown in FIGS. 5and 6, the alignment film made of polyimide or the like is formed on theupper electrode 26 by, for example, the coating method. In this manner,the array substrate AR of the liquid crystal display apparatus 10 isformed.

On the other hand, as shown in FIG. 19, a film made of, for example, ablack resin material is formed on the front surface (first main surface)of the second transparent substrate 30, and is then etched, therebyforming the light shielding portion (black matrix) 31. Next, as shown inFIG. 11, the color filter layer 32 is formed for each subpixel 12 by thephotolithography. Specifically, the color filter layer 32 of red (R),green (G) or B (blue) is formed for each subpixel 12 (see FIG. 1).

Next, as shown in FIG. 19, the overcoat layer 33 made of acrylicphotosensitive resin is formed by, for example, the coating method onthe light shielding portion (black matrix) 31 and the color filter layer32. The overcoat layer 33 is formed so as to cover the light shieldingportion (black matrix) 31 and the color filter layer 32.

Next, as shown in FIG. 20, the photo spacer (spacer portion) 34 made of,for example, acrylic photosensitive resin is formed by thephotolithography on the overcoat layer 33. Thereafter, though not shownin FIG. 12, the alignment film made of polyimide is formed on thesurface of the overcoat layer 33 and the surface of the photo spacer(spacer portion) 34. In this manner, the color filter substrate CF ofthe liquid crystal display apparatus 10 is formed.

The array substrate AR and the color filter substrate CF formed in theabove-described manner are disposed so that the front surfaces (firstmain surfaces), not the rear surfaces (second main surface) thereof, areopposed (opposed disposition). Then, by providing the sealing member(not shown) to the circumference of the array substrate AR and the colorfilter substrate CF disposed to be opposed, the array substrate AR andthe color filter substrate CF are adhered to each other. Thereafter, byfilling the liquid crystal of homogeneous alignment as the liquidcrystal layer LC between the array substrate AR and the color filtersubstrate CF, the liquid crystal display apparatus 10 of the firstembodiment can be obtained.

<Concerning Aperture ratio and Parasitic Capacitance>

FIG. 21 is a plan view that shows a portion near the drain electrode ofone of the subpixels in a liquid crystal display device in accordancewith a comparative example in an enlarged manner. FIG. 22 is across-sectional view taken along the line C-C of FIG. 21. FIG. 23 is across-sectional view taken along the line D-D of FIG. 21.

FIGS. 24 to 26 are cross-sectional views showing the principal partduring manufacturing processes of the liquid crystal display device inaccordance with the comparative example. FIGS. 24 to 26 indicate crosssections corresponding to the cross sections shown in the aforementionedFIG. 22.

Of the liquid crystal display device 110 of the comparative example,those portions except for the portions near the drain electrode are thesame as those portions except for the portions near the drain electrodeof the liquid crystal display device 10 of the first embodiment;therefore, the descriptions thereof will be omitted.

Moreover, in order to help to increase understanding, FIG. 21illustrates a (perspective) state from which the color filter substrateCF is removed. Moreover, to facilitate understanding, FIG. 21 alsoillustrates a state in which, from the array substrate AR, the gateinsulating film 21 (see FIG. 22), the semiconductor layer 22 (see FIG.22), the interlayer resin film (planarization film) 23 (see FIG. 22),the inter-electrode insulating film 25 (see FIG. 22) and the upperelectrode 26 (see FIG. 22) are removed (as a perspective view) so thatthe lower electrode 24 is seen on the uppermost surface. Moreover, tofacilitate understanding, FIG. 21 also illustrates a peripheral portionof a bottom portion 27 a of the contact hole (opening) 27 formed on theinter-electrode insulating film 25 (see FIG. 22).

As shown in FIGS. 21 to 23, in the liquid crystal display device 110 ofthe comparative example also, on the interlayer resin film(planarization film) 23, a hole (opening) 41 that penetrates theinterlayer resin film (planarization film) 23 to reach the drainelectrode DE is formed at a position that is overlapped with the drainelectrode DE, when seen in its plan view. The drain electrode DE isexposed to the bottom portion 41 a of the hole (opening) 41.

On the other hand, on the drain electrode DE exposed to the bottomportion 41 a of the hole (opening) 41, no island-shaped electrode 42(see FIG. 4) is formed. Moreover, when seen in its plan view, the lowerelectrode 24 is formed on the interlayer resin film (planarization film)23 at a region separated from the bottom portion 41 a of the hole(opening) 41.

On the drain electrode DE exposed to the bottom portion 41 a of the hole(opening) 41, on the lower electrode 24, as well as on the interlayerresin film (planarization film) 23 exposed to a region between the drainelectrode DE and the lower electrode 24, when seen in its plan view, theinter-electrode insulating film 25 is formed. On the inter-electrodeinsulating film 25, when seen in its plan view, a contact hole (opening)27 that penetrates the interlayer resin film (planarization film) 23 toreach the drain electrode DE is formed at a position that overlaps withthe drain electrode DE. On the bottom portion 27 a of the contact hole(opening) 27, the drain electrode DE is exposed. On the drain electrodeDE exposed to the bottom portion 27 a of the contact hole (opening) 27as well as on the inter-electrode insulating film 25, the upperelectrode 26 is formed. Therefore, the upper electrode 26 is formed soas to be directly made in contact with the drain electrode DE.

In the manufacturing processes of the liquid crystal display device 110of the comparative example, by carrying out the processes shown in FIGS.7 to 12 in the same manner as in the manufacturing processes of theliquid crystal display device 10 of the first embodiment, the conductivefilm 46 is formed on the drain electrode DE exposed to the bottomportion 41 a of the hole (opening) 41 as well as on the interlayer resinfilm (planarization film) 23.

Thereafter, in the manufacturing processes of the liquid crystal displaydevice 110 of the comparative example, as shown in FIGS. 21 and 24, aportion within a region 144 (see FIG. 21) including the drain electrodeDE and the bottom portion 41 a of the hole (aperture) 41, when seen inits plan view, of the conductive film 46 thus formed is removed by usinga photolithography technique and etching. That is, of the conductivefilm 46, the portion inside the region 144 (see FIG. 21) is bored. Atthis time, on the region 144 inside the opening 43 formed on the lowerelectrode 24, no island-shaped electrode 42 (see FIG. 4) is formed.

Next, as shown in FIG. 25, the inter-electrode insulating film 25 isformed in a manner so as to cover the lower electrode 24, the drainelectrode DE exposed to the bottom portion 41 a of the hole (opening) 41and the interlayer resin film (planarization film) 23 exposed to theregion 144 (see FIG. 21), when seen in its plan view.

Next, of the inter-electrode insulating film 25 thus formed, a portionin which the contact hole (opening) 27 is to be formed is removed byusing a photolithography technique and etching so that a contact hole(opening) 27 that penetrates the inter-electrode insulating film 25 toreach the drain electrode DE is formed. Moreover, the drain electrode DEis exposed to the bottom portion 27 a of the contact hole (opening) 27.

However, as shown in FIG. 26, upon etching the inter-electrodeinsulating film 25, on an edge portion 145 of the bottom portion 27 a ofthe contact hole (opening) 27, the interlayer resin film (planarizationfilm) 23 is scraped off (hollowed) together with the inter-electrodeinsulating film 25. As a result, the width dimension of the contact hole(opening) 27 becomes larger toward the lower side to easily cause areverse-tapered shape in the cross-sectional shape of the contact hole(opening) 27.

In the case when the contact hole (opening) 27 has such areverse-tapered shape in its cross-sectional shape, upon forming theupper electrode 26 on the contact hole (opening) 27, the upper electrode26 is hardly deposited on the edge portion 145 of the bottom portion 27a of the contact hole (opening) 27. As a result, as shown in FIGS. 22and 23, the upper electrode 26 formed on the side surface portion 27 bof the contact hole (opening) 27 and the upper electrode 26 formed onthe bottom portion 27 a of the contact hole (opening) 27 are notconnected with each other as an integral unit, with the result that aso-called “step disconnection or step fault” is caused.

Moreover, as shown in FIG. 21, in the liquid crystal display device 110of the comparative example, the contact hole (opening) 27 is formed onthe same position as that of the hole (openings) 41 in a directionintersecting with the scanning line (gate wiring) 13, for example, alongthe extending direction (Y axis direction of FIG. 21) of the signal line(source wiring) 14.

The region 144 surrounded by the opening 43 formed on the lowerelectrode 24 is given an opening area required for preventing shortcircuiting from occurring between the lower electrode 24 and the upperelectrode 26; therefore, the position of the opening 43 is limited bythe position of the drain electrode DE. Moreover, because of thelimiting conditions of the pixel layout required for achieving both ofthe miniaturization of the subpixel 12 and the improvement of theaperture ratio, the position of the light-shielding unit 31 is limitedby the position of the drain electrode DE. Therefore, since both of theposition of the opening 43 and the position of the light-shielding unit31 are limited by the position of the drain electrode DE, the amount ofallowance by which the position for use in forming the opening 43 isallowed to deviate in the Y axis direction from the position for use informing the light-shielding unit 31 is limited to an extremely smallrange.

In a layout as shown in FIG. 21, one portion 144 a of the region 144surrounded by the opening 43 formed on the lower electrode 24 protrudesin the positive direction of the Y axis direction relative to thelight-shielding unit 31, when seen in its plan view. In this region 144a, since no lower electrode 24 exists, it is not possible to display animage, with the directions of liquid crystal molecules being changed.For this reason, the aperture ratio of the subpixel 12 is substantiallyreduced. That is, an opening loss occurs.

Moreover, the position of the scanning line (gate wiring) 13 is alsolimited by the position of the drain electrode DE. Therefore, since bothof the position of the opening 43 and the position of the scanning line(gate wiring) 13 are limited by the position of the drain electrode DE,the amount of allowance by which the position of the opening 43 isallowed to deviate in the Y axis direction from the position of thescanning line (gate wiring) 13 is limited to an extremely small range.

In the layout shown in FIG. 21, one portion 144 b of the region 144surrounded by the opening 43 is overlapped with one portion of thescanning line (gate wiring) 13, when seen in its plan view. In thisregion 144 b, since no lower electrode 24 exists, the area of theportion at which the scanning line (gate wiring) 13 and the lowerelectrode 24 are overlapped with each other can be reduced by increasingthe area of this region 144 b so that the parasitic capacitance betweenthe scanning line (gate wiring) 13 and the lower electrode 24 can bereduced. However, since the area of the region 144 b is not easilyincreased, it is difficult to reduce the parasitic capacitance. In thecase when the parasitic capacitance cannot be sufficiently reduced, theimage quality of a displayed image tends to deteriorate due tooccurrence of flickers, or the like.

To prevent or suppress the occurrence of such an aperture ratio loss, orto sufficiently reduce the parasitic capacitance between the scanningline (gate wiring) 13 and the lower electrode 24, an arrangement isproposed in which the opening 43 to be formed on the lower electrode 24is formed at a position that deviates from the position of the drainelectrode DE.

However, in the manufacturing processes of the liquid crystal displaydevice in accordance with the comparative example, as described above,upon forming the contact hole (opening) 27 by etching theinter-electrode insulating film 25, the cross-sectional shape of thecontact hole (opening) 27 is prone to be the so-called reverse-taperedshape. Therefore, even in the case when the opening 43 to be formed onthe lower electrode 24 is formed at a position that deviates from theposition of the drain electrode DE, the cross-sectional shape of thecontact hole (opening) 27 is prone to be the so-called reverse-taperedshape, making it difficult to reliably connect the upper electrode 26and the drain electrode DE with each other electrically. In addition, inthe case when the opening 43 to be formed on the lower electrode 24 isformed at a position that deviates from the position of the drainelectrode DE, since the cross-sectional shape of the contact hole(opening) 27 becomes asymmetric to further easily cause areverse-tapered shape, it becomes further difficult to reliably connectthe upper electrode 26 and the drain electrode DE with each otherelectrically.

<Main Features and Effects of the Present Embodiment>

On the other hand, in the liquid crystal display device 10 of thepresent first embodiment, the upper electrode 26 and the drain electrodeDE that is exposed to the bottom portion 27 a of the contact hole(opening) 27 are electrically connected to each other via theisland-shaped electrode 42. Moreover, the island-shaped electrode 42 andthe lower electrode 24 are formed by using the same conductive film 46.

In the present first embodiment, after the hole (opening) 41 has beenformed on the interlayer resin film (planarization film) 23, the lowerelectrode 24 has been formed thereon and the inter-electrode insulatingfilm 25 has been formed thereon, the contact hole (opening) 27 is thenformed. Moreover, on the edge portion 45 (see FIGS. 5 and 6) of thebottom portion 27 a of the contact hole (opening) 27 to be formed, theisland-shaped electrode 42 is sandwiched between the inter-electrodeinsulating film 25 and the interlayer resin film (planarization film) 23so that the inter-electrode insulating film 25 and the interlayer resinfilm (planarization film) 23 are not directly made in contact with eachother. With this structure, upon forming the contact hole (opening) 27,it is possible to prevent or suppress the interlayer resin film(planarization film) 23 from being scraped off (hollowed) together withthe inter-electrode insulating film 25. Moreover, it is also possible toprevent or suppress the width dimension of the contact hole (opening) 27from becoming larger toward the lower side to subsequently cause thereverse-tapered shape in the cross-sectional shape of the contact hole(opening) 27.

Moreover, upon forming the upper electrode 26, the upper electrode 26 isalso deposited on the edge portion 45 (see FIGS. 5 and 6) of the bottomportion 27 a of the contact hole (opening) 27. For this reason, it ispossible to prevent or suppress an occurrence of a problem in which bothof the upper electrode 26, formed on the side surface portion 27 b (seeFIGS. 5 and 6) of the contact hole (opening) 27, and the upper electrode26, formed on the bottom portion 27 a of the contact hole (opening) 27,are not connected with each other as one integral unit, that is, anoccurrence of a so-called “step disconnection or step fault”. As aresult, it becomes possible to reliably connect the upper electrode 26and the drain electrode DE with each other electrically, and to preventdegradation of the image quality of a displayed image, thereby making itpossible to improve the performance of a liquid crystal display device.

Moreover, the island-shaped electrode 42 is formed by processes in whichthe conductive film 46 to form the lower electrode 24 is formed on theentire surface of the array substrate AR and the same conductive film 46thus formed is subjected to a patterning process. With this arrangement,in the process for forming the lower electrode 24, the island-shapedelectrode 42 can be formed simultaneously with the lower electrode 24without the need for adding any new process. Moreover, since theisland-shaped electrode 42 and the lower electrode 24 are formed by thesame conductive film 46, the island-shaped electrode 42 and the lowerelectrode 24 are preferably formed by the same material.

In the liquid crystal display device 10 of the first embodiment,preferably, the contact hole (opening) 27 is formed at a positiondeviating from the hole (opening) 41 in a direction intersecting withthe extending direction (X axis direction) of the scanning line (gatewiring) 13, that is, for example, along the extending direction (Y axisdirection) of the signal line (source wiring) 14. With this arrangement,it is possible to increase the amount of allowance by which, when seenin its plan view, the position at which the opening 43 is formed on thelower electrode 24 is allowed to deviate along the Y axis direction froma position at which the light-shielding unit 31 is formed. Therefore, onthe lower electrode 24, the opening 43 can be formed within a regionthat is overlapped with the light-shielding unit 31, when seen in itsplan view. With this arrangement, it is possible to prevent or suppressthe region 44 surrounded by the opening 43 from protruding in thepositive direction in the Y axis direction, when seen in its plan view,relative to the light-shielding unit 31. Therefore, it is possible toreliably connect the upper electrode 26 and the drain electrode DE witheach other electrically, while preventing or suppressing a reduction ofthe aperture ratio (aperture ratio loss) in the subpixel 12.

More preferably, as shown in FIG. 4, the opening 43 of the lowerelectrode 24 is formed in a manner so as to traverse the scanning line(gate wiring) 13, when seen in its plan view. By forming the opening 43in such a manner as to traverse the scanning line (gate wiring) 13, itis possible to increase the area of the region 44 b that is overlappedwith the scanning line (gate wiring) 13 of the region surrounded by theopening 43, and consequently to reduce the area of the portion at whichthe lower electrode 24 and the scanning line (gate wiring) 13 areoverlapped with each other. Thus, the upper electrode 26 and the drainelectrode DE can be reliably connected with each other electrically,while reducing a parasitic capacitance between the lower electrode 24and the scanning line (gate wiring) 13. As a result, it becomes possibleto prevent or suppress the image quality of a displayed image fromlowering due to an occurrence of flickers or the like, and consequentlyto improve the performance of a liquid crystal display device.

SECOND EMBODIMENT

In first embodiment, the island-shaped electrode is formed on the drainelectrode exposed to the bottom portion of the hole (opening) as well ason the side surface portion of the hole (opening). In contrast, in asecond embodiment, although the island-shaped electrode is formed on thedrain electrode exposed to the bottom portion of the hole (opening), itis not formed on the side surface portion of the hole (opening).

FIG. 27 is a plan view that shows a portion near the drain electrode ofone of the subpixels in a liquid crystal display device according to thesecond embodiment in an enlarged manner. FIG. 28 is a cross-sectionalview taken along the line C-C in FIG. 27.

FIGS. 29 to 31 are cross-sectional views showing the principal partduring manufacturing processes of the liquid crystal display deviceaccording to the second embodiment. FIGS. 29 to 31 show cross sectionscorresponding to the cross sections shown in the aforementioned FIG. 28.

Of a liquid crystal display device 10 a of the second embodiment, thoseportions except for the portions near the drain electrode DE of one ofthe subpixels 12 are the same as those portions except for the portionsnear the drain electrode DE of one of the subpixels 12 of the liquidcrystal display device 10 of the first embodiment; therefore, theexplanations thereof will be omitted.

Moreover, to facilitate understanding, FIG. 27 illustrates a(perspective) state from which the color filter substrate CF is removed.Moreover, to facilitate understanding, FIG. 27 also illustrates a statein which, from the array substrate AR, the gate insulating film 21 (seeFIG. 28), the semiconductor layer 22 (see FIG. 28), the interlayer resinfilm (planarization film) 23 (see FIG. 28), the inter-electrodeinsulating film 25 (see FIG. 28) and the upper electrode 26 (see FIG.28) are removed (as a perspective view) so that the lower electrode 24is seen on the uppermost surface. Moreover, to facilitate understanding,FIG. 27 also illustrates a peripheral portion of a bottom portion 27 aof the contact hole (opening) 27 formed on the inter-electrodeinsulating film 25 (see FIG. 5).

As shown in FIGS. 27 and 28, in the liquid crystal display device 10 aof the present second embodiment also, on the interlayer resin film(planarization film) 23, a hole (opening) 41 that penetrates theinterlayer resin film (planarization film) 23 to reach the drainelectrode DE is formed at a position that is overlapped with the drainelectrode DE, when seen in its plan view. The drain electrode DE isexposed to the bottom portion 41 a of the hole (opening) 41. On thedrain electrode DE exposed to the bottom portion 41 a of the hole(opening) 41, an island-shaped electrode 42 is formed. Moreover, whenseen in its plan view, a lower electrode 24 is formed on the interlayerresin film (planarization film) 23 at a region separated from the bottomportion 41 a of the hole (opening) 41.

On the other hand, in the present second embodiment, the island-shapedelectrode 42 is formed inside a region exposed to the bottom portion 41a of the hole (opening) 41 of the upper surface of the drain electrodeDE, when seen in its plan view.

In the manufacturing processes of the liquid crystal display device 10 aof the present second embodiment, by carrying out the processes shown inFIGS. 7 to 12 in the same manner as in the manufacturing processes ofthe liquid crystal display device 10 of the first embodiment, theconductive film 46 is formed on the drain electrode DE exposed to thebottom portion 41 a of the hole (opening) 41 as well as on theinterlayer resin film (planarization film) 23.

Thereafter, in the present second embodiment, as shown in FIG. 29, aportion within a frame-shaped region 44 (see FIG. 27) of the conductivefilm 46 thus formed is removed by using a photolithography technique andetching. That is, of the conductive film 46, the portion inside theframe-shaped region 44 (see FIG. 27) is bored. At this time, the portioninside the frame-shaped region 44 (see FIG. 27) is bored such that, whenseen in its plan view, the island-shaped electrode 42 is formed insidethe region exposed to the bottom portion 41 a of the hole (opening) 41of the upper surface of the drain electrode DE.

By carrying out a patterning process on the conductive film 46 in thismanner, as shown in FIGS. 27 and 29, a lower electrode 24 composed ofthe conductive film 46 is formed. Moreover, simultaneously with theformation of the lower electrode 24, an opening 43 is formed on thelower electrode 42 so that an island-shaped electrode 42 composed of theconductive film 46 is formed within the opening 43. At this time, thebottom portion 41 a of the hole (opening) 41 is disposed within theopening 43, when seen in its plan view. With this arrangement, it ispossible to prevent the lower electrode 24 (see FIG. 28) and the upperelectrode 26 (see FIG. 28) from causing short circuiting electrically.

Next, as shown in FIG. 30, on the island-shaped electrode 42, on thelower electrode 24 as well as on the interlayer resin film(planarization film) 23 that is exposed to a region (frame-shapedregion) 44 (see FIG. 27) between the island-shaped electrode 42 and thelower electrode 24, when seen in its plan view, an inter-electrodeinsulating layer 25 made of silicon nitride or the like is formed by,for example, a CVD method. That is, the inter-electrode insulating layer25 is formed in a manner so as to cover the island-shaped electrode 42,the lower electrode 24 and the interlayer resin film (planarizationfilm) 23 that is exposed to the region (frame-shaped region) 44 (seeFIG. 27) between the island-shaped electrode 42 and the lower electrode24, when seen in its plan view.

Next, a portion of the inter-electrode insulating film 25 on which thecontact hole (opening) 27 has been formed is removed by using aphotolithography technique and etching. Thus, as shown in FIGS. 27 and31, a contact hole (opening) 27, which penetrates the inter-electrodeinsulating film 25 to reach the island-shaped electrode 42, when seen inits plan view, is formed. Moreover, the island-shaped electrode 42 isexposed to the bottom portion 27 a of the contact hole (opening) 27.

Next, on the island-shaped electrode 42 as well as on theinter-electrode insulating film 25, an upper electrode 26 made of ITO,IZO or the like is formed by using, for example, a sputtering method. Inother words, the upper electrode 26 is formed in a manner so as to coverthe island-shaped electrode 42 and the inter-electrode insulating film25. Thus, as shown in FIG. 28, the upper electrode 26 and the drainelectrode DE are electrically connected with each other via the contacthole (opening) 27. That is, the upper electrode 26 and the drainelectrode DE are electrically connected with each other via theisland-shaped electrode 42.

In the present second embodiment, as shown in FIGS. 27 and 31, uponforming the contact hole (opening) 27, the bottom portion 27 a of thecontact hole (opening) 27 is disposed within a region in which theisland-shaped electrode 42 is formed, when seen in its plan view. Atthis time, on an edge portion 45 of the bottom portion 27 a of thecontact hole (opening) 27, the island-shaped electrode 42 is sandwichedbetween the inter-electrode insulating film 25 and the interlayer resinfilm (planarization film) 23 so that the inter-electrode insulating film25 and the interlayer resin film (planarization film) 23 are notdirectly made in contact with each other. By using such a structure,upon forming the contact hole (opening) 27, it is possible to prevent orsuppress the interlayer resin film (planarization film) 23 from beingscraped off (hollowed) together with the inter-electrode insulating film25. As a result, it is possible to prevent or suppress the widthdimension of the contact hole (opening) 27 from becoming larger towardthe lower side to cause a reverse-tapered shape in the cross-sectionalshape of the contact hole (opening) 27.

Moreover, as shown in FIG. 28, upon forming the upper electrode 26, theupper electrode 26 is also deposited on the edge portion 45 (see FIGS.28 and 31) of the bottom portion 27 a of the contact hole (opening) 27.For this reason, it is possible to prevent or suppress an occurrence ofa problem in which the upper electrode 26, formed on the side surfaceportion 27 b (see FIG. 28) of the contact hole (opening) 27, and theupper electrode 26, formed on the bottom portion 27 a of the contacthole (opening) 27, are not connected with each other as one integralunit, that is, an occurrence of a so-called “step disconnection or stepfault”.

In other words, to prevent or suppress the occurrence of the “stepdisconnection or step fault”, it is only necessary to form theisland-shaped electrode 42 at least inside the region exposed to thebottom portion 41 a of the hole (opening) 41 of the upper surface of thedrain electrode DE.

Additionally, in the example shown in FIG. 27, the contact hole(opening) 27 is formed at the same position as that of the hole(opening) 41 along a direction (Y axis direction) intersecting with theextending direction of the scanning line (gate wiring) 13. In this case,the amount of allowance by which the position for use in forming theopening 43 is allowed to deviate in the Y axis direction from theposition for use in forming the light-shielding unit 31 is not increasedso much. Therefore, in comparison with the first embodiment, the effectfor preventing or suppressing the reduction of the aperture ratio(aperture ratio loss) in each of the subpixels 12 and the effect forreducing the parasitic capacitance between the lower electrode 24 andthe scanning line (gate wiring) 13 are small.

However, even in the case when the contact hole (opening) 27 is formedat the same position as that of the hole (opening) 41 along thedirection (Y axis direction) intersecting with the extending directionof the scanning line (gate wiring) 13, it is possible to obtain theeffect for preventing or suppressing the occurrence of theaforementioned so-called “step disconnection or step fault” of the upperelectrode 26.

THIRD EMBODIMENT

Next, the following description will explain an electronic deviceaccording to a third embodiment. In the first embodiment and secondembodiment, a liquid crystal display device in which the upper electrodeand the drain electrode are electrically connected with each other viaan island-shaped electrode has been explained. In contrast, in the thirdembodiment, an explanation will be given on an electronic device that isprovided with the liquid crystal display device explained in the firstembodiment or second embodiment, by exemplifying a mobile phone.

FIG. 32 is a perspective view showing a mobile phone as one example ofthe electronic device according to the third embodiment.

As shown in FIG. 32, a mobile phone 300 includes the liquid crystaldisplay device of the first embodiment or second embodiment as itsdisplay unit 301, and further provided with a plurality of operationbuttons 302, an ear piece 303 and a mouthpiece 304.

For example, the liquid crystal display device 10 of the firstembodiment or the liquid crystal display device 10 a of the secondembodiment may be used as the display unit 301. Thus, in the displayunit 301, it is possible to prevent a so-called “step disconnection orstep fault” from occurring on the upper electrode, and consequently toreliably connect the upper electrode and the drain electrode with eachother electrically. In particular, when the liquid crystal displaydevice 10 of the first embodiment is used as the display unit 301, itbecomes possible to prevent or suppress the occurrence of an apertureratio loss, or to sufficiently reduce the parasitic capacitance betweenthe scanning line and the lower electrode, with the upper electrode andthe drain electrode being reliably connected with each otherelectrically. Therefore, the performance of the mobile phone serving asan electronic device can be improved.

Additionally, those electronic devices provided with the liquid crystaldisplay device 10 of the first embodiment or the liquid crystal displaydevice 10 a of the second embodiment as the display unit thereof are notlimited to the above-mentioned mobile phone. The liquid crystal displaydevice 10 of the first embodiment or the liquid crystal display device10 a of the second embodiment may be preferably used as a display unitfor various apparatuses, such as, for example, electronic books,personal computers, digital still cameras, liquid crystal televisions,video tape recorders of a view-finder type or a monitor direct-viewingtype, car navigation devices, apparatuses with a pager, and so forth.Moreover, the liquid crystal display device 10 of the first embodimentor the liquid crystal display device 10 a of the second embodiment maybe preferably used as a display unit for various electronic devices,such as electronic pocket notebooks, electronic calculators, wordprocessers, work stations, television telephones (video phones), POS(Point of Sale) terminals, apparatuses provided with touch panels, andso forth. Thus, in any of these electronic devices, it is possible toprevent a so-called “step disconnection or step fault” from occurring onthe upper electrode in the display unit, and consequently to reliablyconnect the upper electrode and the drain electrode with each otherelectrically. In particular, when the liquid crystal display device 10of the first embodiment is used as the display unit, it is possible toprevent or suppress the occurrence of an aperture ratio loss, or tosufficiently reduce the parasitic capacitance between the scanning lineand the lower electrode, with the upper electrode and the drainelectrode being reliably connected with each other electrically.Therefore, the performance of the above-mentioned various electronicdevices can be improved.

In the foregoing, the invention made by the inventors of the presentinvention has been concretely described based on the embodiments.However, it is needless to say that the present invention is not limitedto the foregoing embodiments and various modifications and alterationscan be made within the scope of the present invention.

The present invention is effectively applied to the liquid crystaldisplay devices and the electronic devices.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A liquid crystal display devicecomprising: a first substrate; a second substrate that is disposed so asto be opposed to the first substrate; a first wiring provided on thefirst substrate along a first direction; a second wiring provided alonga second direction intersecting with the first direction; a thin-filmtransistor provided at an intersection between the first wiring and thesecond wiring; a drain electrode electrically connected to the thin-filmtransistor; an organic insulating film formed on the thin-filmtransistor and covering a part of the drain electrode; a first openingthat penetrates the organic insulating film and exposing the drainelectrode; an island-shaped electrode disposed on the first opening andthe organic insulating film, and electrically connected to the drainelectrode; an inorganic insulating film disposed on the organicinsulating film, the drain electrode, and the island-shaped electrodeinside the first opening; a second opening that penetrates the inorganicinsulating film and exposing the drain electrode; and a pixel electrodeformed on the inorganic insulating film and electrically connected tothe island-shaped electrode through the second opening; wherein insidethe first opening, there are a first contact portion in which the drainelectrode and the inorganic insulating film are directly contacted witheach other, and a second contact portion in which the drain electrodeand the island-shaped electrode are directly contacted with each other.2. The liquid crystal display device according to claim 1, wherein thesecond contact portion is closer to the first wiring than the firstcontact portion.
 3. The liquid crystal display device according to claim2, wherein the area of the drain electrode is larger than the area ofthe bottom of the first opening.
 4. The liquid crystal display deviceaccording to claim 3, wherein a peripheral end portion of theisland-shaped electrode is covered with the inorganic insulating film.5. The liquid crystal display device according to claim 4, wherein thesecond opening is formed from the bottom portion of the first openingover the edge portion of the bottom portion to reach the side surfaceportion of the first opening.